Rotating hydraulic roof supporting jacks



June 18, 1957 w. J. JENKINS ROTATING HYDRAULIC ROOF SUPPORTING JACKS Filed Sept. 30. 1952 s Shets-Sheet 1 irdlfnllt A m/mam dZZorzzey.

June 18, 1957 w. J. JENKINS ROTATING HYDRAULIC ROOF SUPPORTING JACKS Filed Sept. 30. 1952 3 Sheets-Sheet 2 nited States Fatent O ROTATING HYDRAULIC ROOF SUPPORTING JACKS William J. Jenkins, Wilkinsburg, Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application September 30, 1952, Serial No. 312,183:

4 Claims. (Cl. 61-45) This invention relates to walking, mine roof-supporting jacks, and particularly to such jacks which are adapted for use in placeswhere maneuverability is of great importance, and to a method of utilizing them to provide an advancing roof support.

An; object of the invention is to provide an improved walking, mine roof-supporting jack unit. Another object is to provide an improved unit of the kind mentioned in which the walking is effected by successive arcuate movements of each of a pair of extensible upright jack devices about the other, each jack device being collapsed, out of contact with'both mine floor and mine roof, and wholly "supported by the other when the latter is sustaining the roof and acting as a pivot for the walking movement. A further obiect is to provide an improved walking jack unit in which power means is provided for effecting the arcuate movements, of the upright jack devices as they are adjusted inturn to effect walking. Another object is to provide tin-improved method of making available an ad vancingroof support. Other objects and advantages of the invention will hereinafter appear.

A desirableapparatus for accomplishing the objects of the present invention may comprise a pair of upright, ,extensible, mine roof-supporting jacksv having connecting means between them which enable each to be swung arcuately' about the other, and desirably each to rotate, in. collapsed condition, relative to the connecting means. Desirabily the mine roof-supporting jacks will, be power extensible and contractible, and hydraulic extension andhydraulic or spring contraction may desirably be provided. Powerrotat'ion or walking is desirable, and motor operated means for-effecting movement of either jack about the axis of the other may desirably be provided. This power operated means may desirably include arrangements whereby either jack may provide a reaction member about which the other is bodily rotatable, and the provision of the reaction may desirably be made automatic upon extension of either jack into engagement with the mine floor and roof and,

terminated by jack contraction; and desirably the source of power (motor) for-effecting walking may be mounted upon the connection between the jack devices which holds them together for movement about each other.

In the accompanying drawings, in which certain illustrative embodiments of the invention are illustrated and in which itsuse is also disclosed,

Figure l is a fragmentary plan. view of a portion of a mine, showing one illustrative embodiment of the invention in use.

Figure 2is a vertical section on the plane of the line 2-2 of Figure 1', looking in a direction. along a longwall face.

Figure 3 is an elevational view of a walking jack. unit according to one embodiment of the invention.

Figure 4 is an enlarged vertical section through one of the jacksof the unit of Figure 3, the view being taken on the plane of the line 4-4 of Figure 3.

Figure 5 is a diagrammatic view showing the mode of advance of a unit of the type. shown in Figures 1, 2 and 3.

an" 1Q Figure 6 is a hydraulic diagram showing one possible system of control for the unit just mentioned.

Figure 7 is a vertical sectionalv view on a plane corresponding to the plane of Figure 4, showing a modified jack device.

Figure 8 is a hydraulic diagram showing one. control system for units employing jacks of the type shown in Figure 7.

Figure 9 is another diagram illustrating the mode of operation of units of the character so far mentioned in the description of the drawings.

Figure 10 is aside elevational view with parts broken away to the plane of the section line 10-10 of Figure 11, showing another form of walking roof supporting unit, parts also being omitted.

Figure 11 is a horizontal section on the plane of the line 11-11 of Figure 10.

Figure 12 is a hydraulic diagram showing a control suitable for'units of the type shown in Figures 10 and 11.

Figure 13 shows a modification of the jack devices such as are shown in Figures 7 and 10.

Referring to the drawings, and first to Figures 1 to 6, there may be noted in Figure l a fragmentary view of a mine which is being operated according to the longwall system and with the use of a continuous miner for detaching the material from the face and delivering it to a conveyor system. A portion of a stall is shown at l and a short section of the longwall face at 2. A conveyor is shown at 3, and a number of walking, roof-supporting jacks are shown, each of these being designated 5. In Figure 2 which, as stated above, is a view looking lengthwise of the longwall face, the various jack units 5 are shown. The conveyor 3 is visable, and a continuous miner, not visible in Figure 1 because it is beyond the top of that view, appears at M.

Referring to Figure 3, there is shown in that figure one of the units 5. This includes a pair of vertical, extensible and contractible jack devices 10, 10, connected together by a connection 11, which includes a bar portion 12' and a pair of eye or ring portions 13', 13, secured at the opposite ends of the bar portion 12. As will later appear, these eye or ring portions 1.3 surround the jacks 10, 10, and the bar 12' and the eyes, while relatively rotatable upon the axis of the jacks, are fixed against relative longitudinal movement, i. e. movement longitudinally of the jacks.

Referring to Figure 4, one of the jacks 10 is illustrated there. This jack is extensible and contractible by fluid pressure. It consists of a cylinder member 15 having an upper head 16 provided with a stufiing box 17. The cylinder member also has a lower head 18, provided with a stuffing box 19. The cylinder member 15 has a bore 21 which is partially separated into opposite chambers by a ported septum 22'. The presence of the ported septum provides a limit device for the movements towards each other of pistons 24 and 25, but permits the action of hydraulic fluid concurrently on the adjacent faces of the two pistons 24 and 25. The-pistons are appropriately packed as at 27, and the upper piston 24 has a piston rod 28 which extends through the stufling box 17, and the lower piston has a piston rod Zfi which extends through the stuffing box 19. The lower piston rod 29' has a mine floor engaging plate or pad 30 secured to it. The upper piston rod 28 has. a mine roof engaging plate- 31 attached to it. Fluid may be supplied to the space between the pistons 24 and 25 through a conduit 33 which extends through the piston rod 28 and piston 24. Fluid can be supplied to the space above the piston 24 through a conduit 35, and to the space below the piston 25' through a conduit 36. Herein,

above its longitudinal center, the cylinder 15 has a col-' the cylinder a substantial distance below the collar 38. Suitable bearing means 41 is arranged between the collars and around the peripheral wall of the cylinder 15, and one of the eye-members 13 is shown in the annular groove which is provided about the periphery of the cylinder 15 between the collars.

In the arrangement described, in use, the jacks 10 are ordinarily alternatively collapsed, and the jack which is extended and which rests on the mine floor and presses its plate 31 against the mine roof, serves as a pivot member about which the ring 13 which is supported by it, rotates, and the jack 10 which is in collapsed condition and which is supported by the arm 12, is manually pushed around the extended jack 10 to the desired extent. Figure shows the walking operation. One of the jacks of a unit is represented by a plain circle. The other is represented by a cross-hatched circle. The rod or connection 12 is also shown. Starting at the bottom of Figure 5, the jack 10 indicated by the cross-hatched circle is collapsed and swung from the lowermost position through the right-hand position to a position directly above the first plain circle representing the other jack 10. Then the jack represented by the plain circle is swung 180, after it has been collapsed and the jack of the crosshatched circle has been extended, about the latter. This procedure continues for as long a time as is necessary. Ordinarily, with the arrangement of jacks shown in Figures 1 and 2, the number of immediately successive adjusting movements of each individual jack unit will not be as numerous as is indicated in Figure 5; and it is possible, by appropriate movements, to position the jacks anywhere that it is desired, and they may be located relatively close together, to the walls of the coal seam, to the conveyor, and to the continuous miner or other veinattacking and disintegrating mechanism, as may be desirable. Figure 9 shows another set-up. Here rows of jack units 5 are arranged at opposite sides of a conveyor 3', and they are indicated as being advanced by rotary movements of 90. The angle of rotation will be determined in any case by the desired results.

In Figure 6 a simple control for one jack unit 5 is shown. A pump P, located in any suitable place, draws fluid from a reservoir RES through a conduit 45 and delivers it under pressure to a conduit 46 which conducts it to a valve box structure 47. This includes a supply box 48 which is of conventional constuction and has a relief valve, not shown, associated with it for controlling the pressure which is to be supplied to the jacks. There are two similar control valve boxes, 51 and S2, and there is a discharge box 53 which is connected back through a discharge line 54 to the reservoir. Conduits 55 and 56 lead from the valve box 51, the first to the connection 33 and the other, through branches 56 and 56", to the connections 35 and 36. The valve box 51 contains a conventional valve, not shown, which is controlled by a handle 58. This handle locates the valve which it controls selectively in mid-position and in opposite end positions. When the valve is in mid-position, fluid may flow freely from the discharge line 46 to the return line 54, but this arrangement may be replaced by one such as is shown in Figure 8, in which there is maintained at all times a constant substantial pressure in the system and no direct connection at any time between the lines 46 and 54. When the handle 58 is moved to one extreme position the valve which it controls supplies pressure to the conduit 55 and vents it from the conduit 56 to the line 54. In the other position of this valve pressure is supplied to the conduit 56 and the line 55 is vented. The other jack 10 is-provided with a corresponding control, and it will be evident that both jacks may be extended and provide roof support at the same time. Both could be collapsed concurrently, but there would be little utility for that to be done under ordinary conditions. Fluid may be trapped in the jacks or, with this set-up, the jacks may be maintained in communication with the pump discharge line when it isdehand jacks 10' sired to maintain them extended. It is probable that maintaining the jacks extended by constant connection with the discharge line 46 may be preferred, under which circumstances the connection 46 will have one or more accumulators, not shown in Figure 6, but arranged as illustrated in Figure 8, connected with it. Neither valve in the valve boxes 51 and 52 can interrupt the availability of fluid to the other.

No further description of this embodiment is necessary, it simply being desirable to have it clearly understood that ordinarily each jack in turn will be extended and held firmly against the mine floor and mine roof while the other is collapsed and moved manually about the first, to reposition it.

In Figures 7 and 8, a somewhat modified jack structure is disclosed, and a relatively constant pressure system is utilized. Referring to Figure 7 it will be noted that the structure of the jack 10' is the same, essentially, as in Figure 4, except that instead of collapsing the jack by bydraulic pressure, resilient means, herein illustrated as springs 60, are arranged between the heads 16' and 18 and the adjacent faces of the pistons 24' and 25. According ly, when fluid is not supplied through the connection 33 and that connection is connected back to the reservoir, the jack will automatically have its pistons moved against the septum 22 by the springs 60. The extension of the jack, however, by fluid pressure, will be the same as in the case of the first embodiment described.

A hydraulic control system for units comprising jacks such as are shown in F'gure 7 is illustrated in Figure 8. Here there is a fluid reservoir R which supplies fluid through a suction line 45' to a pump P, which in turn discharges to a discharge line 46'. The pump P is driven by a motor M, and the operation of the motor is controlled by pressure responsive switch mechanism of conventional form, diagrammatically indicated at 65. This is responsive, to the pressure in the discharge line 46', transmitted to it through a conduit 66. The motor M drives the pump P whenever the pressure in the line 46 is below a desired value, and when the pressure gets to the upper limit of the desired pressure, the motor M will be stopped. The discharge line 46' has connected with it one or more accumulators, these being shown at 68, 68, 68, and leads to a valve box structure 70, from which a return line 71 leads back to the reservoir. Three jack units, 5, 5', 5' are illustrated, and these correspond to the jack units 5 the fact that the jack devices 10' of these units have their contraction elfected by springs, as above described in connection with Figure '7, instead of by hydraulic pressure. The control valve box arrangement 70 is provided with a pair of conventional valve boxes 75 and 76, which have in them valves which do not permit the free flow of fluid from the discharge line 46' to the return line 71, even when the valve elements in these valve boxes are both in centered position. The valve box 75 controls the supply and venting of fluid to one jack 10' of each unit 5'. The valve box 76 controls the flow of fluid relative to the other jack 10' of each unit 5'. Three units are shown for concurrent control. Ordinarily, a very large number of units will not be simultaneously controlled, because of the reduction in roof support which the contraction of a number of jacks simultaneously causes. However, the jacks which are still under pres sure will provide adequate roof support even though a material number of associated jacks are contracted at the same moment. The valve box 75 has its valve controlled conduit 77 connected by branches 77', 77", and 77" to corresponding jacks 10' of the several units 5'. Valve box 76 controls a conduit 78, which is connected by branches 78', 78" and 78" to the several units 5' illustrated. I

No further description of this arrangement is necessary, it sufiicing to point out that when fluid under pressure is supplied to branches 77', 77" and 77" the leftin Figure 8 will be hereinabove first described except forother jacks 10' of the firmly pressed between the floor and roof, while the others will be collapsed by their associated springs because the connections 78', 78" and 78" will at that time be connected to the return line 71.

As previously pointed out, it is desirable not to have to effect the walking action of-the jack units by manually pushing one jack about the axis of the other, and in Figures and 11, and in the hydraulic diagram of Figure 12, there are illustrated means for effecting power walking. Although the means for effecting power walking will be illustrated and described in connection with a roof supporting arrangement embodying a jack structure along the lines of that shown in Fig. 7, it will be understood that such means are equally applicable to a roof supportingarrangement in whichthe jacks are constructed as shown particularly in Fig. 4.

Referring now to Figure 11, it may be noted that the bar structure 12'- is shown as made in the form of a rectangular box to which the eyes or rings 13, 13' are connected. Upon the top of the bar structure 12', there is mounted a casing 81 in which there is contained a drive pinion 82 and pairs of reach gears 83, 84 and 83', 84. The reach gears 83 and 83' mesh with the drive pinion 82 at its opposite sides. The several reach gears are journaled in any suitable manner in the box 81, and the outer reach gears 84 and 84 mesh respectively with gears 85 and 85' which are supported by annuli 86, 86' keyed as at 87 to the cylinder elements 10, 10'.

The drive pinion 82 is driven by a reversible hydraulic motor 90 having connections 91 and 92, each of which serves alternatively as a supply connection or as a vent connection.

Figure 12 shows diagrammatically another control system. In this system a pump P supplies fluid under pressure to a discharge line 46" which difiers from the discharge line 46' of Figure 8 essentially solely in the presence of a check valve C opening in the direction from the pump P towards the valve box structure 70 and preventing opposite flow. The purpose of this check valve is to preclude any danger, in the event of a power failure, of loss of pressure in the jack system should the conduit 77 or 78 at that time be connected through its control valve unit with the pump discharge line. It will be evident that such a check valve arrangement may be incorporated, if desired, in either of the other control systems previously described.

Figure 12 also shows accumulator 68' as well as the accumulators 68. An accumulator 68 is arranged between the control valve unit and one of the jacks 10, in the line 77, while another accumulator 68" is arranged between the other jack 10 and its control box. The ad vantage of this construction is that if the control valves for the jacks are moved to closed position after the jacks have been extended and there is any leakage the accumu lators 68' or 68" will supply the necessary fluid under pressure to maintain the jacks extended. Obviously accumulators may be arranged, in a manner similar to that shown and described with respect to the accumulators 68' and 68", in the other control systems heretofore described, with the result that when they are so installed the several jacks may be cut off, after extension, from the pump discharge line, with no possibility of difliculty, with any normal amount of leakage.

A third difierence between the control system of Fig ure 12 and that of Figure 8 resides in an additional valve box 93 which serves selectively to supply fluid to either of the lines 91 or 92 while venting the other. The lines 91 and 92 may be provided, if desired, with pressure reducing valves 94 and 95 and check valves 96 and 97 and by-pass connections 98 and 99, so that the lines 91 and 92 may be freely vented, but may be supplied with a lower pressure than that which exists in the pump discharge line 46".

It will be observed that when either jack 10 or 10' shown in Figure 12 is collapsed, it will be freely rotatable within its surrounding eye or ring 13. Accordingly, if one of the jacks 10' is extended and firmly held against rotation, the supply of motive fluid to the motor will cause the arm 12' and the collapsed jack 10' to travel around the fixed jack 10' and will (simultaneously, though this is not important to the adjusting function) rotate the collapsed jack on its own axis.

With the pressures which will normally be used in the jacks, the frictional engagement of the packings of the pistons will provide enough resistance to rotation of the cylinder of the extended jack to cause the collapsed jack to'travel around the extended jack, but if it is desired to provide positive assurance. that when the jacks are extended, andhave their support plates firmly engaged with the mine. bottom, the jack cylinders cannot rotate, there may be provided a rod. 100'fixed to the bottom plate 30' and extending through an opening in an car 101 secured to the lower end of the cylinder 15',

It will be. evident that, the roof-supporting jack mechanisms illustrated and described are simple, rugged, readily controlled, permit extreme flexibility of repositioning, provide adequate roof support, and that their method of use provides :a form of advancing roof support of a highly advantageous nature.

While their are in this application specifically described, with respect to the apparatus aspect of the invention, one form, a modification thereof, a second iiorm, and a modification applicable to either form, and one illustrative practice of the invention from its method aspect, it is to be understood that these are disclosed for purposes of illustration and that the invention may be otherwise modified, embodied, and practiced without departing from its spirit or the scope of the appended claims.

What is claimed is:

l. A walking mine roof-supporting jack unit comprising upright expansible and contractible jack devices having a bar with an eye at each end, each eye rotatably surrounding one of said jack devices, fior connecting said jack devices for selective rotation of either about the axis of the other when the latter is expanded into roofsupporting relation and the first is contracted, each of said jack devices having a gear surrounding the same, and said bar supporting a motor and a gear train driven by said motor and engaging each of said gears for rotating each of the latter on its own axis and bodily about the axis of the other.

2. A walking mine roof-supporting jack unit comprising upright extensible and contractible jack devices, a bar, means at each end of the bar rotatably associated with one of said jack devices, for connecting said jack devices vfor selective rotation of either about the axis of the other when the latter is contracted, each of said jack devices having a gear associated with the same and nonrotatable when the jack which supports it is extended, and a motor and a gear train supported on said bar and engageable with one of said gears for causing said bar and the other jack device to revolve about the axis of said gear.

'3, In combination, a plurality of rooiengaging, expansible chamber-type supporting jacks, connecting means between each pair of said jacks for connecting the same for rotation of either about the axis of the other, gear means supported on said connecting means and a fluid motor for effecting rotation of said .gear means, a gear on each of said jacks cooperating with said gear means for effecting rotation of one jack about the other upon supply of fluid to said motor, connections to each jack for controlling extension and contraction thereof, connections to said motor for effecting reverse operation thereof, a pum a driving motor for said pump, a pump discharge line, a return line, a suction line leading to said pump, a reservoir with which said suction line and said return line communicates, a relief valve controlled connection from said discharge line to said return line, accumulator means connected with said discharge line, a control for said motor responsive to the pressure in said discharge line, and valve boxes, one controlling the extension and collapse of one jack, another controlling the extension and collapse of the other jack and a third controlling the driving of said motor selectively in opposite directions.

4. In a walking roof jack mechanism, the combination comprising a pair of upright, spaced apart, parallel, axially extensible roof jacks, power operated means for extending and retracting said jacks into and out of roof supporting position, a rigid barlike connection between said jacks, means for pivotally connecting said barlike connection to both of said jacks whereby either jack when released may swing with said barlike connection horizontally about the upright axis of the other jack, power operated mechanism operatively connected between said jacks and said barlike connection for swinging said harlike connection to move either jack in an arcuate path relative to the other, said swinging mechanism including rotating means on said barlike connection and operative connections between said rotating means and each of said jacks to effect rotation of said harlike connection and retracted jack relative to said extended jack, and control means including shiftable control elements operatively connected to said power oper- Med means for eatending and retracting said jacks and to said power operated mechanism for swinging said baa-like connection and positionable to control said jacks and said 'References Cited in the file of this patent UNITED STATES PATENTS 1,704,918 Morgan Mar. 12, 1929 1,870,088 Beckwith Aug. 2, 1932 2,420,755 M'avor May 20, 1947 2,623,739 Thomas etal. Dec; 30, 1952 2,641,906 Knights at al June 16, 1953 2,657,028 Joy Oct. 27, 1953 v FOREIGN PATENTS Great Britain I an. 9, 1947 

